Positioning apparatus for a power tong

ABSTRACT

A positioning apparatus for moving a power tong (110) between an operative and an inoperative position is a drilling tower (105) comprises a first arm (102) and a second arm (103). One end of the first arm (102) is pivotally connected to one end of the second arm (103) at pivot (106) whilst the other end of both the first arm (102) and the second arm (103) are pivotally mounted on a beam (104) attached to the drilling tower (105). Both arms (102, 103) can be extended and retracted in unison to move the power tong (110) towards and away from its operation position circumjacent a pipe string.

This invention relates to a positioning apparatus for moving a powertong between an operative and an inoperative position in a drilling rig.

Power tongs are used to connect and disconnect threaded tubulars used inthe construction of oil and gas wells.

Typically, for example as shown in U.S. Pat. No. 3 799 009, power tongsare suspended by a cable attached to a support member high in thedrilling tower. When it is desired to connect or disconnect two threadedtubulars the power tong is manually swung into position and closedcircumjacent the tubulars. When the operation is completed the powertong is released and allowed to swing back into an inoperative position.

Manoeuvring the power tong requires considerable strength and is verydifficult when the power tong is designed for handling large diametertubulars and is thus very heavy.

In EP-A-0 593 803 (which was not published until after the priority dateof this application) the Applicants describe a positioning apparatus forassisting in the positioning of power tongs. Whilst this positioningapparatus allows a power tong to be easily manipulated it is stilldesirable to have a rig hand in the immediate vicinity of the tubularsto ensure that the power tong is correctly placed on the tubulars.

The present invention, at least in its preferred embodiments, aims toobviate the need for a rig hand in the immediate vicinity of the powertong.

According to the present invention there is provided a positioningapparatus for moving a power tong between an operative and aninoperative position in a drilling tower, which positioning apparatuscomprises a first arm and a second arm, one end of said first arm beingpivotally mounted to one end of said second arm and the other end ofboth said first arm and said second arm being pivotally mountable onsaid drilling tower with said first arm and said second arm convergingtowards one another, and means for extending and retracting said firstarm and said second arm.

Preferably, the positioning apparatus includes a beam and the other endof both said first arm and said second arm are pivotally mounted on saidbeam.

Advantageously, the positioning apparatus includes means for extendingand retracting said first arm and said second arm in unison.

In one embodiment, at least one of said first and second arms is formedby the interconnection of two chains the links of one of which chainsare provided with blocking members which can co-operate with the linksof the other chain to form said arm.

In another embodiment at least one of said first and second arms isformed by a piston and cylinder which is preferably double acting.

In a further embodiment, at least one of said first and second armscomprises a rack which can be moved by rotation of a pinion or a wormdrive engaged therewith.

Preferably, the positioning apparatus includes a cable for supportingsaid first arm and said second arm in a generally horizontal plane.

The present invention also provides a drilling tower provided with apositioning apparatus in accordance with the present invention.

Preferably, said first arm and said second arm are supported in agenerally horizontal plane.

Advantageously, said one ends of said first arm and said second arm arepivotally mounted together about a generally vertical axis and saidother ends of said first arm and said second arm are pivotally mountedabout a generally vertical axis.

Preferably, said other ends of said first arm and said second arm arepivotally mounted for movement about a generally horizontal axis.

Advantageously, said drilling tower includes a power tong supported bysaid positioning apparatus.

Preferably, said power tong is supported via two support members whichare attached one to either side of said power tong and are attached torespective ends of said arms to either side of the pivotal connectionthereof.

For a better understanding of the present invention reference will nowbe made, by way of example, to the accompanying drawings, in which:

FIG. 1 is a plan view of one embodiment of a positioning apparatus inaccordance with the present invention;

FIG. 2 a side elevation of the positioning apparatus shown in FIG. 1;

FIG. 3 a perspective view of the positioning apparatus shown in FIGS. 1and 2 in use in a drilling tower;

FIG. 4 is a plan view of a second embodiment of a positioning apparatusin accordance with the present invention; and

FIG. 5 is a plan view of a third embodiment of a positioning apparatusin accordance with the present invention.

Referring to FIGS. 1 to 3 of the drawings there is shown a positioningapparatus which is generally identified by reference numeral 101.

The positioning apparatus 101 comprises two arms 102, 103 of variablelength which are pivotally mounted on a beam 104 attached to a drillingtower 105.

The arms 102, 103 and the beam 104 together form a support trianglelying in a substantially horizontal plane.

The arms 102, 103 are pivotally interconnected at hinge 106 by means ofend plates 107 and 108.

A cable 109 (FIG. 3) is secured between a support member high in thedrilling tower 105 and the hinge 106.

A power tong 110 driven by a motor 130 is suspended from the supporttriangle by two rods 111, 112 which extend from opposite sides of thepower tong 110 to the end plates 111 and 112.

Each of the arms 102 and 103 forms part of a mechanism 113 which isdescribed in detail in EP-A-0 593 803 which is fully incorporated hereinfor all purposes. In particular the mechanism 113 comprises two chains114 and 115. Each link of chain 114 is provided with a blocking member116.

When a hydraulic motor 117 is rotated anti-clockwise as viewed in FIG. 2the links of the chain cooperate with the blocking members 116 to formarm 102 which is relatively rigid.

A connecting rod 118 connects the mechanism 113 to a similar mechanism119 so that when the hydraulic motor 117 is rotated both arms 102 and103 extend and retract in unison.

When it is desired to make-up or break-out a joint hydraulic motor 117is actuated so that the arms 102 and 103 extend and the power tong 110is moved to an operative position as shown in full lines in FIG. 3. Whenthe operation is complete the hydraulic motor 117 is reversed and thearms 102 and 103 contract to move the power tong 110 to an inoperativeposition shown in chain lines in FIG. 3.

Each arm 102, 103 is pivotally mounted on the beam 104 by hinges 120,121 respectively which pivot inwardly and outwardly as the arms 102, 103are retracted and extended respectively.

The positioning apparatus 101 is operated from a remote control panel122.

The positioning apparatus 101 shown in FIG. 4 is generally similar tothat shown in FIG. 1 except that the arms 202 and 203 comprise doubleacting piston and cylinder assemblies which may be hydraulically orpneumatically operable, the former being recommended for precise controlas hydraulic fluid is substantially incompressible. If desired, the arms202, 203 could comprise single acting piston and cylinder assembliesacting against a return spring.

In the positioning apparatus 301 shown in FIG. 5 the arms 302, 303comprise racks which can he extended and retracted by rotation ofpinions 323 and 324 by hydraulic motor 317.

It will be noted that in all the embodiments described the hinges 106,206, 306, 120, 220, 320, 121, 221 and 321 all pivot about a generallyvertical axis. In addition, it may he desirable to mount the ends of thearms remote from the hinges 106, 206, 306 for pivotal movement about agenerally horizontal axis to accommodate the small vertical movement ofhinges 106, 206, 306 as the arms are extended and retracted caused bythe fixed length of the cable 109. This could conceivably be achieved bymodifying the hinges or, alternatively, mounting the beam 104 forpivotal movement about a generally horizontal axis on the drilling tower105.

What is claimed is:
 1. A positioning apparatus for moving a power tongbetween an operative and an inoperative position in a drilling tower,said power tong driven by a motor, which positioning apparatus comprisesa first arm and a second arm one end of said first arm being pivotallymounted to one end of said second arm and the other end of both saidfirst arm and said second arm being pivotally mountable on said drillingtower with said first arm and said second arm converging towards oneanother, means for extending and retracting said first arm and saidsecond arm.
 2. A positioning apparatus as claimed in claim 1, includinga beam, wherein said other end of both said first arm and said secondarm are pivotally mounted on said beam.
 3. A positioning apparatus asclaimed in claim 1, including means for extending and retracting saidfirst arm and said second arm in unison.
 4. A positioning apparatus asclaimed in claim 1, wherein at least one of said first and second armsis formed by the interconnection of two chains the links of one of whichchains are provided with blocking members which can co-operate with thelinks of the other chain to form said arm.
 5. A positioning apparatus asclaimed in claim 1, wherein at least one of said first and second armsis formed by a piston and cylinder.
 6. A positioning apparatus asclaimed in claim 5, wherein said piston and cylinder is double acting.7. A positioning apparatus as claimed in claim 1, wherein at least oneof said first and second arms comprises a rack which can be moved byrotation of a pinion or a worm drive engaged therewith.
 8. A positioningapparatus as claimed in claim 1, including a cable for supporting saidfirst arm and said second arm in a generally horizontal plane.
 9. Apositioning apparatus for moving a power tong between an operative andan inoperative position in a drilling tower, said power tong driven by amotor, which positioning apparatus comprises a first arm end a secondarm one end of said first arm being pivotally mounted to one end of saidsecond arm and the other end of both said first arm and said second armbeing pivotally mountable on said ddrilling tower with said first armand said second arm converging towards one another, and means forextending and retracting said first arm and said second arm, and meansfor extending and retracting said first arm and said second arm inunison.
 10. A positioning apparatus as claimed in claim 9, including abeam, wherein said other end of both said first arm and said second armare pivotally mounted on said beam.
 11. A positioning apparatus asclaimed in claim 9, wherein at least one of said first and second armsis formed by the interconnection of two chains the links of one of whichchains are provided with blocking members which can co-operate with thelinks of the other chain to form said arm.
 12. A positioning apparatusas claimed in claim 9, wherein at least one of said first and secondarms is formed by a piston and cylinder.
 13. A positioning apparatus asclaimed in claim 12, wherein said piston and cylinder is double acting.14. A positioning apparatus as claimed in claim 9, wherein at least oneof said first and second arms comprises a rack which can be moved byrotation of a pinion or a worm drive engaged therewith.